| 1 | package live |
| 2 | |
| 3 | import ( |
| 4 | "sync" |
| 5 | "testing" |
| 6 | "time" |
| 7 | ) |
| 8 | |
| 9 | // recv waits for one message, or fails. Every test wants this and none |
| 10 | // of them vary the timeout. |
| 11 | func recv(t *testing.T, s *Sub, what string) Message { |
| 12 | t.Helper() |
| 13 | select { |
| 14 | case m := <-s.C(): |
| 15 | return m |
| 16 | case <-time.After(2 * time.Second): |
| 17 | t.Fatalf("%s: received nothing", what) |
| 18 | return Message{} |
| 19 | } |
| 20 | } |
| 21 | |
| 22 | func TestPublishReachesEverySubscriberOnTheTab(t *testing.T) { |
| 23 | h := NewHub() |
| 24 | a := h.Subscribe(7) |
| 25 | b := h.Subscribe(7) |
| 26 | defer a.Close() |
| 27 | defer b.Close() |
| 28 | |
| 29 | h.Publish(7, Message{Version: 3, Data: []byte(`{"v":3}`)}) |
| 30 | |
| 31 | for i, s := range []*Sub{a, b} { |
| 32 | if m := recv(t, s, "subscriber"); m.Version != 3 { |
| 33 | t.Errorf("subscriber %d got version %d, want 3", i, m.Version) |
| 34 | } |
| 35 | } |
| 36 | } |
| 37 | |
| 38 | // The tab id is the whole routing key. If it leaks, one team's edits |
| 39 | // paint into another sheet's grid. |
| 40 | func TestPublishDoesNotReachAnotherTab(t *testing.T) { |
| 41 | h := NewHub() |
| 42 | here := h.Subscribe(7) |
| 43 | elsewhere := h.Subscribe(8) |
| 44 | defer here.Close() |
| 45 | defer elsewhere.Close() |
| 46 | |
| 47 | h.Publish(7, Message{Version: 3}) |
| 48 | |
| 49 | recv(t, here, "the subscribed tab") |
| 50 | select { |
| 51 | case m := <-elsewhere.C(): |
| 52 | t.Fatalf("a subscriber on tab 8 received tab 7's message: %+v", m) |
| 53 | case <-time.After(50 * time.Millisecond): |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | func TestPublishWithNoSubscribersIsFine(t *testing.T) { |
| 58 | // One person editing alone is the common case, not an edge case. |
| 59 | NewHub().Publish(7, Message{Version: 1}) |
| 60 | } |
| 61 | |
| 62 | func TestCloseUnsubscribes(t *testing.T) { |
| 63 | h := NewHub() |
| 64 | s := h.Subscribe(7) |
| 65 | if got := h.Subscribers(7); got != 1 { |
| 66 | t.Fatalf("Subscribers(7) = %d after one Subscribe, want 1", got) |
| 67 | } |
| 68 | s.Close() |
| 69 | if got := h.Subscribers(7); got != 0 { |
| 70 | t.Fatalf("after Close, Subscribers(7) = %d, want 0", got) |
| 71 | } |
| 72 | // An SSE handler defers Close and may also reach it on a write |
| 73 | // error. A double close must not panic in a goroutine no request |
| 74 | // owns. |
| 75 | s.Close() |
| 76 | } |
| 77 | |
| 78 | func TestClosingOneSubscriberLeavesTheOthers(t *testing.T) { |
| 79 | h := NewHub() |
| 80 | a := h.Subscribe(7) |
| 81 | b := h.Subscribe(7) |
| 82 | defer b.Close() |
| 83 | a.Close() |
| 84 | |
| 85 | h.Publish(7, Message{Version: 9}) |
| 86 | if m := recv(t, b, "the surviving subscriber"); m.Version != 9 { |
| 87 | t.Fatalf("surviving subscriber got version %d, want 9", m.Version) |
| 88 | } |
| 89 | } |
| 90 | |
| 91 | // A tab that has stopped reading must never block the writer: the |
| 92 | // publisher is a request handler that has already committed a database |
| 93 | // write. |
| 94 | func TestASlowSubscriberIsDroppedNotBlocking(t *testing.T) { |
| 95 | h := NewHub() |
| 96 | s := h.Subscribe(7) |
| 97 | defer s.Close() |
| 98 | |
| 99 | for i := 0; i < subBuffer+10; i++ { |
| 100 | done := make(chan struct{}) |
| 101 | go func(i int) { |
| 102 | h.Publish(7, Message{Version: uint64(i)}) |
| 103 | close(done) |
| 104 | }(i) |
| 105 | select { |
| 106 | case <-done: |
| 107 | case <-time.After(2 * time.Second): |
| 108 | t.Fatalf("Publish blocked on message %d — one wedged browser would hold a writer open", i) |
| 109 | } |
| 110 | } |
| 111 | if !s.Lost() { |
| 112 | t.Fatal("an overrun subscriber is not marked lost; it would paint a grid with holes in it") |
| 113 | } |
| 114 | } |
| 115 | |
| 116 | func TestAKeepingUpSubscriberIsNotLost(t *testing.T) { |
| 117 | h := NewHub() |
| 118 | s := h.Subscribe(7) |
| 119 | defer s.Close() |
| 120 | for i := 0; i < subBuffer*3; i++ { |
| 121 | h.Publish(7, Message{Version: uint64(i)}) |
| 122 | recv(t, s, "keeping up") |
| 123 | } |
| 124 | if s.Lost() { |
| 125 | t.Fatal("a subscriber that read every message was declared lost") |
| 126 | } |
| 127 | } |
| 128 | |
| 129 | // Subscribe, Publish and Close all race in production: a tab opening |
| 130 | // while another closes while an edit lands. |
| 131 | func TestConcurrentSubscribePublishAndClose(t *testing.T) { |
| 132 | h := NewHub() |
| 133 | var wg sync.WaitGroup |
| 134 | for i := 0; i < 20; i++ { |
| 135 | wg.Add(2) |
| 136 | go func() { |
| 137 | defer wg.Done() |
| 138 | s := h.Subscribe(7) |
| 139 | s.Close() |
| 140 | }() |
| 141 | go func() { |
| 142 | defer wg.Done() |
| 143 | h.Publish(7, Message{Version: 1, Data: []byte("x")}) |
| 144 | }() |
| 145 | } |
| 146 | wg.Wait() |
| 147 | if got := h.Subscribers(7); got != 0 { |
| 148 | t.Fatalf("Subscribers(7) = %d after every subscriber closed, want 0", got) |
| 149 | } |
| 150 | } |
| 151 | |
| 152 | // An instance that has served many tabs over a week must not keep one |
| 153 | // empty map per tab it has ever seen. |
| 154 | func TestAnEmptiedTabIsForgotten(t *testing.T) { |
| 155 | h := NewHub() |
| 156 | for id := uint64(1); id <= 50; id++ { |
| 157 | h.Subscribe(id).Close() |
| 158 | } |
| 159 | h.mu.Lock() |
| 160 | n := len(h.tabs) |
| 161 | h.mu.Unlock() |
| 162 | if n != 0 { |
| 163 | t.Fatalf("the hub still holds %d tab entries after every subscriber left", n) |
| 164 | } |
| 165 | } |
| 166 | |
amadan